Revert "i2c: fix stack buffer overflow vulnerability in i2c md command"

This reverts commit 8f8c04bf1ebbd2f72f1643e7ad9617dafa6e5409.

The commit is largely wrong and breaks most of i2c command functionality.
The problem described in the aforementioned commit commit message is valid,
however the commit itself does many more changes unrelated to fixing that
one problem it describes. Those extra changes, namely the handling of i2c
device address length as unsigned instead of signed integer, breaks the
expectation that address length may be negative value. The negative value
is used by DM to indicate that address length of device does not change.

The actual bug documented in commit 8f8c04bf1ebbd2f72f1643e7ad9617dafa6e5409
can be fixed by extra sanitization in separate patch.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Nicolas Iooss <nicolas.iooss+uboot@ledger.fr>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/cmd/i2c.c b/cmd/i2c.c
index bd04b14..9050b2b 100644 (file)
--- a/cmd/i2c.c
+++ b/cmd/i2c.c
@@ -200,10 +200,10 @@ void i2c_init_board(void)
  *
  * Returns the address length.
  */
-static uint get_alen(char *arg, uint default_len)
+static uint get_alen(char *arg, int default_len)
 {
-       uint    j;
-       uint    alen;
+       int     j;
+       int     alen;
 
        alen = default_len;
        for (j = 0; j < 8; j++) {
@@ -247,7 +247,7 @@ static int do_i2c_read(struct cmd_tbl *cmdtp, int flag, int argc,
 {
        uint    chip;
        uint    devaddr, length;
-       uint    alen;
+       int alen;
        u_char  *memaddr;
        int ret;
 #if CONFIG_IS_ENABLED(DM_I2C)
@@ -301,7 +301,7 @@ static int do_i2c_write(struct cmd_tbl *cmdtp, int flag, int argc,
 {
        uint    chip;
        uint    devaddr, length;
-       uint    alen;
+       int alen;
        u_char  *memaddr;
        int ret;
 #if CONFIG_IS_ENABLED(DM_I2C)
@@ -469,8 +469,8 @@ static int do_i2c_md(struct cmd_tbl *cmdtp, int flag, int argc,
 {
        uint    chip;
        uint    addr, length;
-       uint    alen;
-       uint    j, nbytes, linebytes;
+       int alen;
+       int     j, nbytes, linebytes;
        int ret;
 #if CONFIG_IS_ENABLED(DM_I2C)
        struct udevice *dev;
@@ -589,9 +589,9 @@ static int do_i2c_mw(struct cmd_tbl *cmdtp, int flag, int argc,
 {
        uint    chip;
        ulong   addr;
-       uint    alen;
+       int     alen;
        uchar   byte;
-       uint    count;
+       int     count;
        int ret;
 #if CONFIG_IS_ENABLED(DM_I2C)
        struct udevice *dev;
@@ -676,8 +676,8 @@ static int do_i2c_crc(struct cmd_tbl *cmdtp, int flag, int argc,
 {
        uint    chip;
        ulong   addr;
-       uint    alen;
-       uint    count;
+       int     alen;
+       int     count;
        uchar   byte;
        ulong   crc;
        ulong   err;
@@ -985,7 +985,7 @@ static int do_i2c_loop(struct cmd_tbl *cmdtp, int flag, int argc,
                       char *const argv[])
 {
        uint    chip;
-       uint    alen;
+       int alen;
        uint    addr;
        uint    length;
        u_char  bytes[16];